Thursday, February 16, 2012

EVOLUTIONARY ADVANTAGE OF ZEBRA’S STRIPES

Susanne Akesson (Lund University/Sweden), Gábor Horváth (Hungary) and others have conducted experiments in optics and insect feeding on a farm near Budapest populated with horses and sucking blood horseflies. According to the researchers, black and white stripes of zebras will serve as camouflage, hiding them from hungry lions and tigers and also to ward off horseflies, more eager to blood horses of a unique color. The study examined the attraction of horseflies to different types of panels crossed by black and white stripes of varying width. According to Akesson, horseflies are attracted to horizontally polarized light, because this phenomenon will help them to identify aquatic stretches where to copulate and leave their eggs. The arrangement of zebra stripes (especially white), prevents the polarized light to be reflected. The more narrow white stripes, the less likely to attract horseflies, conferring an evolutionary advantage to zebras.